But a less theological explanation finds support from an experiment conducted at a British college psychology department: Maybe that common element of modern religions was the product of Darwinian evolution.

Refreshments are sold on the honor system in the break room at the University of Newcastle - people who get a cup of coffee or tea are supposed to leave money. Researchers found that when they added a picture of eyes above the payment box, more than twice as much money was deposited, compared with weeks when the eyes were replaced by a picture of flowers.

People were subconsciously triggered into acting more honestly, as if they were actually being watched, even though they knew the eyeballs were mere paper and ink.

Those results, published last month in the journal Biology Letters ("Cues of being watched enhance cooperation in a real-world setting": Abstract), support a controversial theory that connects prehistoric humans to modern faiths. [subconscious]